1. Field of the Invention
The present invention relates to an antenna, and especially relates to a multi-band antenna structure which is suitable for different frequency bands.
2. Description of the Related Art
In recent years, wireless communication technology is rapidly developed. Long term evolution (LTE) communication technology is provided. The frequency bands of LTE700/2300/2500 comprise 704-960 MHz and 1710-2690 MHz, covering five frequency bands of wireless wide area network (WWAN). Comparing to the conventional wireless local area network (WLAN) 2.4G and 5G antenna, the LTE antenna covers lower frequency and wider bandwidth. Therefore, it needs to pay attention to both antenna multi-band operation and receiving quality for the antenna design.
However, when the conventional multi-band antenna is manufactured, it comprises a plurality of antennas which are manufactured by using sheet metal press forming technology, and the antennas are bended and electrically connected on a single printed circuit board, so that the antennas form a dual polarization array multi-band antenna structure. Or the patterns of the antennas are printed on the copper film of the printed circuit board by using printing technology, and then the patterns of the antennas are manufactured by using exposal, development and etching technology. Plural printed circuit boards with the patterns of the antennas are stacked as a dual polarization array multi-band antenna structure. The multi-band antenna structure can be used in different frequency bands when receiving or transmitting signals.
Both of the multi-band antennas mentioned above comprise a plurality of antennas, so that the volume and size of the multi-band antennas are larger and the cost is increased. Moreover, installing the multi-band antenna is difficult because the signal feeding points of the multi-band antennas are on different faces or locations.